Dispersive Micro Research Articles

Simple and rapid determination of tartrazine in fake saffron using the metal organic framework (Fe SA MOF@CNF) by HPLC/PDA

The present study of a novel metal–organic framework containing Fe single atoms doped on electrospun carbon nanofibers (Fe SA-MOF@CNF) based on dispersive micro solid phase extraction (D-μ-SPE) using HPLC–PDA for detection tartrazine in fake saffron samples was designed. The Fe SA-MOF@CNF sorbent was extensively characterized through various techniques including N2 adsorption–desorption isotherms, X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The specific area of surface of the sorbent was 577.384 m2/g. The study variables were optimized via the central composite design (CCD), which included a sorbent mass of 15 mg, a contact time of 6 min, a pH of 7.56, and a tartrazine concentration of 300 ng/ml. Under the optimum condition, the calibration curve of this method was linear in the range of 5–1000 ng/mL, with a correlation coefficient of 0.992. The LOD and LOQ values were ranged 0.38–0.74 and 1.34–2.42 ng/ml, respectively. This approach revealed significant improvements, including high extraction recovery (98.64), recovery rates (98.43–102.72%), and accuracy (RSDs < 0.75 to 3.6%). the enrichment factors were obtained in the range of 80.6–86.4 with preconcentration factor of 22.3. Consequently, the D-μ-SPE method based on synthesized Fe SA-MOF@CNF could be recommended as a sustainable sorbent for detecting tartrazine in saffron samples.

Zn-doped CeO2 nanorod based dispersive solid phase micro-extraction of lead in water, black pepper, lentils and tea samples

In this work, pristine CeO2 and Zn-doped CeO2 nanorods were prepared through facile hydrothermal process and characterized. The Zn-dopied CeO2 was first used for dispersive solid phase micro extraction (d-SPµE) of lead in water and food. The conditions affecting d-SPµE of lead were optimized. They were pH, adsorption/elution contact time, and eluent type/volume/concentration, interfering ion effects and sample volume. The sample pH, eluent concentration/volume and sample volume were 3, 2molL-1 HCl/1mL and 60mL, respectively. The adsorption/desorption kinetics of the developed d-SPµE were very fast, and the extraction time was only 30s (30s for adsorption and without vortexing for elution). The preconcentration factor (PF) and limit of detection (LOD) of the d-SPµE for lead were 60 and 2.0µgL-1, respectively. The RSD% (n=5) of the extraction method was found to be ≤ 3.0%. The high tolerable interfering ions concentrations were obtained. The sorbent could be used for 46 times. The method was confirmed with analyses of NW-TMDA 54.6 Lake water, SPS-WW1 Batch 114 wastewater and NIST Tomato Leaves 1573a certificate reference materials. The trace lead concentrations in wastewater, dam water, river water, sea water, tea, lentils, and black pepper were determined by d-SPµE-FAAS.

Development of a dispersive micro solid phase extraction-HPLC method for the simultaneous quantification of antiepileptic drugs in various matrices

Due to the widespread utilization of antiepileptic drugs for seizure control and patient well-being, it is crucial to determine their presence in biological and water samples. This is essential for optimizing therapy, comprehending drug behavior, identifying drug interactions, monitoring environmental contamination, and safeguarding public health and ecology. Hence, a novel method that combines dispersive micro solid phase extraction with HPLC-DAD was developed to simultaneously determine the presence of Lacosamide, Levetiracetam, and Phenytoin. To achieve this, a new sorbent was synthesized using the hydrothermal and sol–gel methods, which consisted of bimetallic MIL-100 (Fe, Ni) on MIL-100 (Mn), SiO2, and Fe3O4 nanoparticles. We compared the extraction capabilities of several sorbents in order to select the most effective one. The optimal ratio of components for the chosen sorbent was determined through the simplex lattice design to enhance its efficiency. The optimized values for SiO2, Fe3O4, and MIL-100 (Fe, Ni) on MIL-100 (Mn) were found to be 0.1, 0.34, and 0.56, respectively. The parameters that affected the dispersive micro solid phase extraction method were optimized using both experimental design and one factor at a time. Under the optimal conditions, the linear range for the detection of Lacosamide, Levetiracetam, and Phenytoin was determined to be 0.1–363.0, 0.3–372.0, and 0.4–435.0 ng mL−1, respectively, with low LODs below 0.13 ng mL−1. Additionally, a preconcentration factor of 492.6, 487.1, and 469.5 was achieved for measuring Lacosamide, Levetiracetam, and Phenytoin, respectively. The intra-day and inter-day relative standard deviations (RSDs) ranged from 3.8 % to 4.6 % and 4.2 % to 5.2 %, respectively. The recoveries and RSDs for analyzing real water, human urine, and serum samples were found to be between 89.6–97.0 % and 4.53–6.44 %, respectively.

Trace Determination of Phenanthrene and Fluorene in Beverages Using D-μ-SPE and Liquid Chromatography Analysis

Dispersive micro solid phase extraction (D-μ-SPE) method using Graphene Oxide (GO) for the extraction and pre-concentration of selected polycyclic aromatic hydrocarbons (PAHs) from beverage samples prior to high-performance liquid chromatography - diode array detector (HPLC - DAD) is reported. Selected PAHs Fluorene (FLU) and Phenanthrene (PHE) were used as targeted analytes. An experimental design using Response Surface Methodology (RSM) and Box–Box–Behnken design (BBD) was performed to evaluate the interactive effects of three significant parameters: mass of sorbent, sample volume and extraction time. Under the optimum conditions, the method revealed good linearity (R2 = 0.9995 – 0.9998) over a concentration range of 0.5 – 5.0 mg L-1. The limit of detection (LOD) was in the range of 0.03 – 0.24 mg L-1 with satisfactory relative recoveries (81 – 99 %) and good relative standard deviation (RSD) of ≤ 3.80 % (n = 3). The method was successfully applied to tea, coffee, and milk samples and proved to be a simple, rapid, and reliable method with good extraction efficiencies for the detection of PAHs in beverage samples.

Synthesis of the magnetic composite of Ni-MOF-I in aqueous medium and its application in magnetic dispersive micro solid phase extraction of plasticizers from pharmaceutical samples

For the first time, this research presents the synthesis procedure and analytical application of Ni-MOF-I magnetic composite. The synthesis method was green and done in an aqueous medium. The composite was employed as an adsorbent in a magnetic dispersive solid phase extraction process followed by dispersive liquid–liquid microextraction for the extraction and preconcentration of some plasticizers from pharmaceutical samples stored in plastic containers. The Ni-MOF-I magnetic composite was characterized by applying Fourier transform infrared spectrophotometry, vibrating sample magnetometry, scanning electron microscopy, energy-dispersive X-ray, X-ray diffraction, and nitrogen adsorption/desorption analyses. For operating the extraction procedure, initially, the plasticizers were adsorbed onto the adsorbent particles by vortexing. Then, the plasticizers were desorbed from the adsorbent surface using a mL volume of 2-proponal. Subsequently, the obtained eluate phase was mixed with a mixture of 1,2-dibromoethane and 1,1,2-trichloroethane and then injected into deionized water using a glass syringe. Afterward, centrifugation was done to isolate the extractant from the aqueous phase. Eventually, one microliter of the sedimented phase was injected into gas chromatography-flame ionization detection. Acceptable analytical results such as high enrichment factors (355–415) and extraction recoveries (71–83 %), low limits of quantification (0.76–1.08 μg L−1) and detection (0.23–0.33 μg L−1), wide linear ranges (1.08–300 μg L−1), and satisfactory relative standard deviation values of 4.0–6.3 % (intra-day precision, n = 5) and 4.9–7.4 % (inter-day precision, n = 5) were achieved. The suggested procedure was used as a productive analytical method based on the Ni-MOF-I magnetic composite for the extraction and determination of some plasticizers from different pharmaceutical samples filled in plastic containers. Elimination of centrifugation, using 2-propanol as a green desorption/disperser solvent, detection of di-(2-ethylhexyl) phthalate in boric acid alcohol drop, and applying µL-level of the extraction solvent are the advantages of this proposed method.

A novel deep eutectic solvent modified magnetic covalent organic framework for the selective separation and determination of trace copper ion in medicinal plants and environmental samples

BackgroundPretreatment techniques should be introduced before metal ion determination because there is very low content of heavy metals in Chinese medicinal plants and environmental samples. Magnetic dispersive micro solid phase extraction (MDMSPE) has been widely used for the separation and adsorption of heavy metal pollutants in medicinal plants and environmental samples. However, the majority of MDMSPE adsorbents have certain drawbacks, including low selectivity, poor anti-interference ability, and small adsorption capacity. Therefore, modifying currently available adsorption materials has gained attention in research. ResultsIn this study, a novel adsorbent MCOF-DES based on a magnetic covalent organic framework (MCOF) modified by a new deep eutectic solvent (DES) was synthesized for the first time and used as an adsorbent of MDMSPE. The MDMSPE was combined with inductively coupled plasma optical emission spectrometry (ICP-OES) for selective separation, enrichment, and accurate determination of trace copper ion (Cu2+) in medicinal plants and environmental samples. Various characterization results show the successful preparation of new MCOF-DES. Under the optimal conditions, the enrichment factor (EF) of Cu2+ was 30, the limit of detection (LOD) was 0.16 μg L−1, and the limit of quantitation (LOQ) was 0.54 μg L−1. The results for the determination of Cu2+ were highly consistent with those of inductively coupled plasma mass spectrometry (ICP-MS), which verified the accuracy and reliability of the method. SignificanceThe established method based on a new adsorption material MCOF-DES has achieved the selective separation and determination of trace Cu2+ in medicinal and edible homologous medicinal materials (Phyllanthus emblica Linn.) and environmental samples (soil and water), which provides a promising, selective, and sensitive approach for the determination of trace Cu2+ in other real samples.

A phenomenological constitutive model of Novel Rheo Gravity Die Cast Al-15Mg2Si-4.5Si-0.01Sr-0.015B composite

The present study discusses the high temperature deformation behaviour as well as phenomenological constitutive model development of the novel Rheo gravity die cast (RGDC) Al-15Mg2Si-4.5Si-0.01 Sr-0.015B composite. Within the scope of the study, uniaxial isothermal compression tests are performed on the RGDC Al-15Mg2Si-4.5Si-0.01 Sr-0.015B composite, covering a range of strain rates from 10−3 to 10 s−1 and deformation temperatures spanning from 250 °C to 450 °C. Analysis using X-ray Diffraction (XRD), Energy dispersive spectroscopy (EDS) and Electron Probe Micro Analyzer (EPMA) revealed the presence of distinct phases within the material, including primary Al, Mg2Si, and elemental Si. The study employed three different constitutive models i.e., the Johnson-Cook (JC), modified Johnson-Cook (mJC), and sine hyperbolic Arrhenius (shA) types, to predict the flow stress of the material as a function of strain, strain rate, and deformation temperature. The results indicated that the sine hyperbolic Arrhenius type model and the modified Johnson Cook model effectively accounted the coupling effect of strain, strain rate, and deformation temperature, which affect the flow stress. Statistical analysis, specifically Pearson coefficient correlation (R), average absolute relative error (AARE) and standard deviations, established a reasonable agreement between the predicted flow stress values and the experimental flow stress data. Furthermore, it is observed that the sine hyperbolic Arrhenius type model exhibited superior accuracy compared to the modified Johnson Cook model, particularly at higher strain levels.

Interference free ultratrace beryllium determination in alkaline effluents of beryllium processing plants by graphite furnace atomic absorption spectrometry after a novel graphene oxide-assisted dispersive micro solid phase extraction without using a chelating agent

Ultratrace level determination of beryllium is carried out using graphene oxide as a dispersive micro solid phase extractant in alkaline beryllium processing plant effluents.

Synthesis and evaluation of a chitosan nanomaterial as efficient sorbent for determination of fungicide residues in waters and wine by liquid chromatography high resolution mass spectrometry.

In the present study a novel, cost-effective, environmentally friendly, and efficient analytical method was developed to analyze fungicide residues in water and wine. The method relies on the application of a newly developed sorbent nanomaterial named Nano-Cs-NAT, synthesized by modifying chitosan, a naturally occurring, low-cost polysaccharide, through grafting with two acrylic monomers and a cross-linker. Nano-Cs-NAT was introduced as analytical sorbent for Dispersive Micro Solid Phase Extraction (D-μ-SPE) before Liquid Chromatography-Orbitrap High-Resolution Mass Spectrometry (LC-Orbitrap HRMS) analysis of twelve fungicides commonly used in viticulture (among the others, triazoles, strobilurines and N-substituted imidazoles). Characterization of the sorbent was conducted, confirming the successful acrylation of chitosan. A multivariate approach was employed to optimize D-μ-SPE extraction parameters. The material was found to be highly effective in simultaneously purifying and concentrating the target analytes, enhancing overall analytical efficiency and sensitivity. The Nano-Cs-NAT-D-μ-SPE-LC-Orbitrap-HRMS method was thoroughly validated, exhibiting good recoveries (72-104%), reproducibility (average RSD ≤ 6%) and repeatability (average RSD ≤ 7%). It also achieved low limits of detection (LOD) in river water (average LOD of 0.04 μg L-1) and wine (average LOD of 0.72 μg kg-1), highlighting its potential for routine fungicide residue analysis. This developed method addresses environmental and food safety concerns by providing an efficient solution for detecting fungicide residues in waters and wine.

Extraction and preconcentration of parabens from the human follicular fluid through dispersive micro solid phase extraction using microporous MIL-68 (In) followed by in-situ effervescence-boosted dispersive liquid-liquid microextraction

For the first time in this study, a microextraction method was developed to perform follicular fluid safety assessment analysis. The drastic importance of follicular fluid safety on the proper nourishment and development of oocytes caused the development of the present method. Since women are regularly exposed to parabens through cosmetics, healthcare, and hygienic products, the infection of body fluids is probable in long-term exposures. Also, for the first time, MIL-68 (In) was applied in an analytical method. Moreover, a new method called in-situ effervescence-boosted dispersive liquid-liquid microextraction was adopted for the simultaneous derivatization and preconcentration of the target parabens. To perform the method, 25 mg of MIL-68 (In) was dispersed into the solution of follicular fluid by vortexing. Then, 1.0 mL of 2-propanol was used to elute the analytes from the absorbent via vortexing. The analyte-enriched organic phase was mixed with 100 µL of acetic anhydride (derivatization agent) and 27 µL 1,2-dibromoethane (extraction solvent) which was swiftly injected into a sodium carbonate solution. Following the centrifugation, the extraction solvent was sedimented at the bottom of a conical bottom glass test tube and an aliquot of it was injected into a gas chromatograph equipped with a flame ionization detector. Wide linear ranges (120–25000 µg L-1), satisfactory extraction recoveries (31–79%) and enrichment factors (31−79), and appreciable limits of detection (7–36 µg L-1) and quantification (25–120 µg L-1) were recorded. The high surface area of MIL-68 (In) (608.82 m2 g-1) and its significantly low average pore diameter (13.829 A°) provide an ideal platform for the extraction of parabens from the complex matrix of follicular fluid.

Synthesis of novel MOF-on-MOF composite as a magnetic sorbent to dispersive micro solid phase extraction of benzodiazepine drugs prior to determination with HPLC-UV

Diazepam and lorazepam are two benzodiazepine drugs widely prescribed as antidepressants and antiepileptics. A straightforward and time-save dispersive micro solid phase extraction method as a sample preparation strategy was developed to extract these drugs in human urine and real water samples prior to their determination by HPLC-UV. A novel sorbent based on growing Co-MOF on Fe-MOF was synthesized and then magnetized using magnetic Fe3O4 nanoparticles and a sol–gel strategy. The sorbent (Fe3O4@SiO2@Co-MOF@Fe-MOF composite) showed the highest extraction efficiency toward diazepam and lorazepam compared to Fe-MOF and Co-MOF@Fe-MOF as sorbents. The effects of various factors on diazepam and lorazepam determination were studied by experimental design, in which a Plackett-Burman design and Box-Behnken design were used for screening the factors and optimizing the significant factors, respectively. Under optimum conditions, the method linearity for the diazepam and lorazepam determination was 0.3–450 and 0.2–400 ng mL−1 with an R2 of 0.9926 and 0.9943, respectively. Proper detection limits of 0.09 and 0.06 ng mL−1 were obtained for the diazepam and lorazepam determination. Also, intra-day and inter-day RSDs (n = 3) were in the range of 3.42–3.75 % and 4.76–5.39 % for the diazepam and lorazepam determination, respectively. The method exhibits a high preconcentration factor of 654.3 and 719.1 for the diazepam and lorazepam determination. Besides, the recoveries and RSDs were evaluated by analysis of tap, river, and well water, and two human urine samples using the method. RSDs were in the range of 3.09–6.80 %, with recoveries between 88.2 and 97.5 % for analysis of spiked real water and urine samples.

New biological monitoring method for 1-Naphthol and 2-Naphthol based on stir bar sportive dispersive micro extraction strategy using magnetic ionic liquid

Naphthalene is one of the few volatile bicyclic aromatic hydrocarbons and a white crystalline solid that can sublimate at room temperature. Since 2000, according to the results of animal studies on the carcinogenic effects of naphthalene, this substance has been recognized as a major problem for the environment and industrial environments. Exposure to naphthalene leads to kidney toxicity, hemolytic anemia and other health problems in the human body. The International Agency for Cancer has placed naphthalene in group 2B (probably carcinogenic to humans). 1- naphthol and 2- naphthol are biological urinary indicators of human exposure to naphthalene in work environments. For the first time in this research, the concentration of 1-naphthol and 2-naphthol in urine, which serves as an indicator of naphthalene exposure, was performed through a method known as magnetic ionic liquids-based disperse liquid–liquid microextraction (MIL-DLLME). Subsequently, the samples were analyzed using gas chromatography with a flame ionization detector (GC-FID). Additionally, the factors that influence the extraction of this metabolite, such as the quantity of extracting solvent, speed of mixing, proportion of salt added, duration of mixing, and pH value, were determined using both a two-level factorial test design and a central composite design. Calibration curves were developed under optimal conditions, and the validity of the developed microextraction method was studied with different statistical methods and the analysis of real samples. A strong linear correlation between the subpeak level and the corresponding concentrations was observed in the range of 0.5–0.002 μg/ml for 1-naphthol and 2.00–0.001 µg mL-1for 2-naphthol. In addition, the detection limit and quantitative detection limit for 1-naphthol were 0.0006 µg mL−1, 0.002 µg mL−1, and 0.0003 µg mL−1, 0.001 µg mL-1for 2-naphthol respectively. The MIL-DLLME extraction method can be regarded as an environmentally friendly microextraction technique since it eliminates the need for dispersing solvents and toxic organic solvents as extractants. Results showed that the proposed technique can be applied for biological monitoring of the biomarkers of naphthalene in the exposed workers during occupational or environmental assessments.

Molecularly imprinted dispersive micro solid-phase extraction and tandem derivatization for the determination of histamine in fermented wines.

Histamine causes allergic reactions and can serve as an indicator for assessing food quality. This study designed and developed a dispersive micro solid-phase extraction (D-μSPE) method that combined the advantages of dispersive liquid-liquid extraction and solid-phase extraction (SPE). Molecularly imprinted polymers (MIPs) were employed as the solid phase in the D-μSPE method to extract histamine in wine samples. We used microwave energy to significantly reduce the synthesis time, achieving an 11.1-fold shorter synthesis time compared to the conventional MIP synthetic method. Under optimized D-μSPE conditions, our results showed that the dispersive solvent could effectively increase the adsorption performance of MIPs in wine samples by 97.7%. To improve the sensitivity of histamine detection in gas chromatography-mass spectrometry, we employed the microwave-assisted tandem derivatization method to reuse excess derivatization reagents and reduce energy consumption and reaction time. Calibration curves were constructed for wine samples spiked with 0-400 nmol histamine using the standard addition method, resulting in good linearity with a coefficient of determination of 0.999. The intra- and inter-batch relative standard deviations of the slope and intercept were < 0.7% and < 5.3%, respectively. The limits of quantitation and detection were 0.4 nmol and 0.1 nmol, respectively. The developed method was successfully applied to analyze the histamine concentration in 10 commercial wine samples. In addition, the AGREEprep tool was used to evaluate the greenness performance of the developed method, which obtained a higher score than the other reported methods.

The simultaneous measurement of atomoxetine, venlafaxine, and duloxetine in actual water and biological samples requires the creation of a unique magnetic dispersive micro solid phase extraction sorbent based on MOF-on-MOF

ABSTRACT Atomoxetine, venlafaxine, and duloxetine are three antidepressant drugs widely prescribed to treat this disorder. Determining these drugs is a major challenge due to their low concentration and high matrix effects on biological samples. Dispersive micro solid phase extraction was developed as a sample preparation strategy to extract these drugs in real water and biological samples. A novel sorbent containing a magnetic MOF-on-MOF was prepared to extract these drugs using Fe3O4 nanoparticle and Sol-gel technique. The microextraction procedure was optimised under two steps using experimental design. Three factors, including pH, sorbent amount, and desorption solvent volume, significantly affected the extraction of analytes and optimised using a central composite design. The optimum value of pH, sorbent amount, and desorption solvent volume was 29 mg, 6.5, and 150 µL. Under optimum conditions, the linear ranges for measuring atomoxetine, venlafaxine, and duloxetine in water samples were 1.42–496, 0.43–472, and 0.73–459 ng mL−1, respectively. The detection limits of atomoxetine, venlafaxine, and duloxetine were 0.4, 0.1, and 0.2 ng mL−1. High and proper preconcentration factors ranged from 462.4–511.4 in distiled water samples and 450.7–489.8 in urine samples were obtained to determine atomoxetine, venlafaxine, and duloxetine with three concentrations of 5.0, 20.0, and 100.0 ng mL−1, respectively. Inter-day and intra-day RSD% were calculated by triplicate determination of atomoxetine, venlafaxine, and duloxetine at three concentrations of 10.0, 50.0 and 100.0 ng mL−1 and were between 3.2–4.3% and 3.8–4.6% in distiled water samples, and 4.8–5.7% and 5.0–5.8% in urine samples, respectively. Analysis of tap, river water, and two urine samples as real water and biological samples under optimum conditions exhibited recovery and standard deviation in the ranges of 90.2–96.9% and 3.84–5.74%, respectively, confirmed the proper ability of the method to determine atomoxetine, venlafaxine, and duloxetine in natural water and biological samples.

Evolution behavior and kinetic analysis of vacuum-extruded iron-rich dust briquette in blast furnace

The vacuum extrusion iron-rich dust briquette was prepared by vacuum extrusion of iron ore concentrates, blast furnace dust and Portland cement. The evolution behavior and kinetic analysis of briquette in blast furnace was studied by high temperature process interrupted experiment. The phase transformation, metallurgical strength, microstructure and three-dimensional structure of dust briquette during high temperature reduction process were analyzed by X-ray diffraction, scanning electron microscope, energy dispersive spectroscopy and micro computed tomography. It is found that the high temperature reduction process of briquette can be divided into six stages, and the mechanical strength of briquettes under reducing atmosphere decreases with the increase of reduction degree and metallization rate, from 4.58 KN at 100 °C to 0.52 KN at 1100 °C. As the temperature increases, the metal iron and porosity inside briquette gradually increase. The ratio of the volume of metallic iron at 700 °C, 900 °C and 1100 °C was 1.47%, 3.70% and 6.60%, and the porosity is 10.32%, 34.1% and 47.1%, respectively. Furthermore, the non-isothermal kinetic reduction process of briquette was analyzed, and the evolution mechanism was revealed. The reduction process of briquettes is mainly controlled by diffusion, and only in the fourth stage (510 °C–840 °C) is limited by the reduction reaction of magnetite and decomposition reaction of calcium carbonate. This paper provides a theoretical support for the efficient and economical recycling of dust in iron and steel enterprises.

Synergy of iron-natural phenolic microparticles and hydrophobic ionic liquid for enrichment of tetracycline residues in honey prior to HPLC-UV detection

Iron-natural phenolic microparticles were developed as absorbents for dispersive micro solid phase extraction (D-μSPE) synergistic with hydrophobic ionic liquid (IL) for dispersive liquid–liquid microextraction (DLLME) to enrich tetracycline residues, including tetracycline, doxycycline, oxytetracycline and chlortetracycline. In situ iron microparticles synthesized from betel nut natural reagent were employed as an adsorbent for D-μSPE. The hydrophobic IL [Hmim][PF6] was synergistically utilized as an extraction solvent to extract and accumulate adsorbents bound with tetracyclines before quantitation by HPLC-UV. The synergistic combination of DLLME with D-μSPE provided excellent extraction recovery compared with individual extraction. The developed method was successfully applied to enrich and determine tetracycline residues in honey samples, with recoveries ranging from 80.0 to 121.5% and providing high enrichment factors ranging from 61 to 197. This alternative method is simple and rapid, with high extraction efficiency and a high enrichment factor and is also environmentally friendly for the analysis of tetracyclines.

NiCo2O4@ZnCo2O4 nanomaterial for selective and fast dispersive solid phase micro-extraction of manganese and lead in water, tea and cinnamon samples followed by FAAS determination

NiCo2O4@ZnCo2O4 nanomaterial was synthesized and XRD, FTIR, FESEM, zeta potential measurements, and BET were used for characterization. It was first used as a sorbent for simultaneous dispersive solid phase micro extraction (d-SPµE) of manganese and lead in water, tea and cinnamon. The determination of analytes was made by FAAS. The pH, elution conditions, sample volume, contact times, and effect of competing ions on the d-SPµE of manganese and lead was examined. The optimal pH, and eluent for manganese and lead were found to be 4 and 2 mol/L hydrochloric acid (3 mL), respectively. The adsorption was carried out without vortexing and contact time for elution was only 30 s. The LOD and PFs of the d-SPµE for manganese and lead were 1.7 μg L−1, 16.7 for manganese and 4.0 μg L−1, 33.3 for lead, respectively. The tolerable concentrations of interfering ions for analytes were rather high. The accuracy of d-SPµE was confirmed with analyses of BCR-482 Lichen, TMDA-70.2 Lake water, and NIST RM 8704 Buffalo River Sediment and applying d-SPµE to spiked sea water, wastewater, dam water, tea and cinnamon.

One-pot/one-step synthesis of Bi2O3/ZnO/Pd nanocomposite for preconcentration and determination of some heavy metal ions in different samples

ABSTRACT In this contribution, a new green eco-friendly synthesised nanocomposite (Bi2O3/ZnO/Pd) was fabricated by one-pot/one-step method, using ultrasonic waves. The nanocomposite was used for pre-concentration of some heavy metals, i.e. cadmium (II), lead (II), and copper (II), exploiting ultrasound-assisted dispersive micro solid phase extraction (UA-D-μ-SPE) method, before their determination by flame atomic absorption spectroscopy (FAAS). The adsorbent synthesis was confirmed by XRD, SEM, BET, TEM, EDS, and TGA analyses. The central composite design (CCD) method was employed to optimise various parameters affecting the extraction of heavy metals. The effective parameters in the adsorption process, viz. the amount of adsorbent (16 mg), pH of the sample solution (6.2), and adsorption time (4 min), were optimised. The type and the concentration of eluting agent (HCl solution) was investigated as one parameter at a time. Impressive parameters in the desorption stage such as the volume and concentration of eluting solution (400 μL of 0.8 mol L−1 HCl) and desorption time (2.5 min) were optimised. In the best extraction conditions for cadmium (II), lead (II), and copper (II), the limits of detection (LODs) were 0.75, 2.1, and 0.90 ng mL−1; the limits of quantification (LOQs) were 2.5, 7.0, and 3.0 ng mL−1; the linear dynamic ranges (LDRs) were 2.5–100, 7.0–600, and 3.0–250 ng mL−1; preconcentration factors (PF) were 24.10, 25.20, and 25.39; and the relative standard deviations (RSDs%) were 3.7, 4.1, and 3.8 (n = 5), respectively. Additionally, the adsorbent had the ability to extract metals up to 8 times without a significant decrease in the extraction percentages. The adsorbent was successfully used in the determination of cadmium (II), lead (II), and copper (II) ions in different food, biological, cosmetic, and water samples.

Molecularly imprinted dispersive micro solid-phase extraction coupled with high-performance liquid chromatography for the determination of four aflatoxins in various foods

A new dummy template-based molecularly imprinted dispersive micro solid-phase extraction (MI-d-µSPE) coupled with HPLC-FLD developed for the simultaneous determination of four aflatoxins (B1, B2, G1, G2) in various food matrices. The synthesized MIP was used as a dispersive solid-phase extraction (dSPE) sorbent for aflatoxins extraction. The chemometric approach was used to identify the optimum conditions of dSPE. The results showed the amount of MIP sorbent (55 mg), adsorption time (12.5 min), and %ACN (75%) were significant extraction parameters. The method has a detection limit in the range of 0.059–0.208 µg kg−1 and a quantification limit in the range of 0.197–0.694 µg kg−1 for aflatoxins. The intra- and inter-day precision was less than 5%, and recoveries were 79.1–109.4%. The expanded uncertainty of the developed method was found to be 2.9–22.8%. The new MI-d-µSPE with HPLC-FLD method was applied for 37 food matrices.

Carbon nanotubes/metal-organic framework based magnetic dispersive micro-solid phase extraction for the determination of triazole fungicides in wastewater and soil samples

In this research, the magnetic dispersive micro solid phase extraction (M−D-µ-SPE) method was used for pre-concentration and trace detection of triazole fungicides in agricultural wastewater and soil samples. The nano sorbent used for M−D-µ-SPE is based on a magnetic carbon nanotubes/Cu-based MOF (M−MWCNT−Cu−BDC) nanocomposite, which was synthesized and characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, vibrating-sample magnetometer, and Nitrogen adsorption-desorption analysis. The effective parameters on the extraction performance were optimized, and under the optimized conditions (pH value: 7.0; the amount of sorbent: 30 mg; extraction time: 30 min; desorbing agent: ethanol; the volume of desorbing solvent: 500 μL and desorption time: 5 min), the limits of detection (LOD) was 0.45 ng mL−1, and the linear range was 1.50 to 750 ng mL−1 with a correlation coefficient higher than 0.993. The repeatability (RSD%) of the method for five replicates ranged from 2.8 to 5.5%. High recoveries (91–94%) and excellent preconcentration factor (PF = 91–94) were also obtained. Finally, this method was applied to determine triazole fungicides in agricultural wastewater and soil samples.